Conventional fuel injector isolating members are disclosed in U.S. Pat. No. 7,293,550, entitled “Fuel Injector Isolation Seat,” and United States Patent Application Publication No. 2007/0113828, entitled “Fuel Injector Isolating and Sealing Member.”
FIG. 1 illustrates a front view of a conventional fuel injector system 10 within a cylinder head 12 of an internal combustion engine. The cylinder head 12 includes a stepped injector bore 14 that receives at least a portion of the fuel injector system 10. The fuel injector system 10 includes a main body 16 and a tip 18 extending axially from the main body 16.
The injector bore 14 includes a main chamber 20 into which the main body 16 of the fuel injector system 10 is positioned. The injector bore 14 also includes a tapered chamber 22 into which the tip 18 passes.
In operation, the fuel injector system 10 delivers a predetermined amount of fuel directly to a combustion chamber 24. An annular combustion seal 26 is secured around a shaft of the tip 18. The combustion seal 26 sealingly engages a portion of the cylinder head proximate an end of the tapered chamber 22 and the tip 18, thereby preventing gases within the combustion chamber 24 from passing upwardly into the tapered chamber 22.
An annular alignment ring 28 is seated on an internal ledge 30 of the cylinder head 12 proximate the junction of the main chamber 20 and the tapered chamber 22. The alignment ring 28 is typically a metal ring that provides a hard contact point between the cylinder head 12 and the main body 16 of the fuel injector system 14. Although, as shown and described in U.S. Pat. No. 7,293,550, an elastomeric ring member and a cupped spring washer may be used instead of the isolation ring 28 shown in FIG. 1.
In general, however, the alignment ring provides the same spring rate during the entire range of engine operation. Moreover, a separate component is typically used to ensure that an isolation ring secures between the fuel injector system to the isolation ring.